Published · not in PSIPUB-BASS-II-LIMITSInvestigation dossier

BASS-II limits

BASS-II flammability-limit points (published)

Principal investigator: not stated in source
Platform: ISS MSG / 1-g lab
Hardware: not stated in source
Dates: not stated in source
Licence: not stated in source
Status: published values, not in PSI; shown only when “Include published evidence” is on

Source document (opens in a new tab)ntrs.nasa.gov/citations/20210011385

Evidence proximity, not a safety rating. This page describes what was tested and where each value comes from.

Footprint · Microgravity

Where BASS-II limits’s runs sit in condition space, in the Atlas chart window. Other investigations’ runs in this regime are dimmed.

1 of 2 runs drawn · 1 run without O₂ or pressure is not drawn.

Source: NASA PSI run tables (snapshot 2026-11-14) and the published papers listed under Sources. Evidence proximity, not a safety rating; not a hazard map.

Objective

No objective text; see the source document.

Fingerprint COMPUTED

Computed from the 2 records below: what varied, what was held constant, and what was never recorded.

Varied

O₂ 13.5–15.4 % · 2 levels · reported limit

Held constant

Pressure 101.3 kPa · nominal (stated, not measured)
Flow 4.0 cm/s · nominal (stated, not measured)

Not recorded

Pressure missing in 1 of 2 rows · not reported in source
Flow missing in 1 of 2 rows · not reported in source

Condition axes: what varied and what was held constant
Axis	State	Range	Basis	Recorded
O₂	varied	13.5–15.4 % · 2 levels	reported limit	2/2
Pressure	held constant	101.3 kPa	nominal (stated, not measured)	1/2
Flow	held constant	4.0 cm/s	nominal (stated, not measured)	1/2

Placeable: 2 of 2 record O₂ and can be placed (the engine can compute a distance); 1 also record pressure and appear on the charts.
Gravity: Microgravity (1) · Earth (1 g) (1)
Fuel classes: Solid · thick (2)
Flow regime: concurrent flow (2)
Materials (2): Cast PMMA rods, concurrent flow (1) · Cast PMMA rods, 1-g upward spread (1)
Outcomes: not recorded (2)
Measured quantities: none normalized beyond O₂, pressure and flow
Data-quality flags: limit-value × 2: A reported limit: a threshold inferred by the authors from a test series, not a tested condition.
nominal-value × 2: A value stated in a document, not measured in this run.

Where the runs sit: O₂ × pressure, zoomed to the data

1 of 2 runs record both ambient O₂ and pressure and are plotted. 1 are not: 1 run: O₂ recorded but pressure not recorded.

Microgravity 1 runs

reported limit: not a tested condition
reference atmosphere

Source: the normalized O₂ and pressure of each run in the run table below (NASA PSI run tables or the cited paper); the original cell and any conversion are in each run’s provenance. Reference atmospheres are MARGIN’s presets. Not a hazard map.

Published records

Values transcribed from the paper (published, not a PSI table row), with the source locator and verification state of each record.

BASS-II limits: 2 records.

BASS-II limits: 2 records. Each value cell shows the normalized value and, beneath it, the original cell as it appears in the source.
Record	Inspect	Material	Fuel class	g	O₂ %	Pressure kPa	Flow cm/s	Outcome	Flags	Source locator	Verification
micro-min		Cast PMMA rods, concurrent flow	Solid · thick	µg	13.5 limittranscribed	101.3 nominaltranscribed	not recordedconcurrent flowtranscribed	not recorded	limit-value, nominal-value	Olson et al., BASS-II Summary Report, NASA/TM-20210011385 · §6.1.4.4, p. 76 (PDF p. 84)“13.5 percent O2 at a of 8 to 12 s⁻¹ is significantly lower than the observed upward flame spread limit of 15.4 percent O2”	PUBLISHEDchecked against primary source · §6.1.4.4, p. 76 (PDF p. 84)
1g-upward		Cast PMMA rods, 1-g upward spread	Solid · thick	1 g	15.4 limittranscribed	not recordedtranscribed	4.0 nominalconcurrent flowtranscribed	not recorded	limit-value, nominal-value	Olson et al., BASS-II Summary Report, NASA/TM-20210011385 · §6.1.4.4, p. 76 (PDF p. 84)“15.4 percent O2 (in normal gravity with an additional 4-cm/s forced flow (Ref. 23))”	PUBLISHEDchecked against primary source · §6.1.4.4, p. 76 (PDF p. 84)

Investigation dossier

Loading dossier…

Reading the record, its runs and their sources.

BASS-II limits

BASS-II flammability-limit points (published)

Principal investigator

not stated in source

Platform

ISS MSG / 1-g lab

Hardware

not stated in source

Dates

not stated in source

Licence

not stated in source

Status

published values, not in PSI; shown only when “Include published evidence” is on

Evidence proximity, not a safety rating. This page describes what was tested and where each value comes from.

Fingerprint COMPUTED

Computed from the 2 records below: what varied, what was held constant, and what was never recorded.

Varied

O₂ 13.5–15.4 % · 2 levels · reported limit

Held constant

Pressure 101.3 kPa · nominal (stated, not measured)
Flow 4.0 cm/s · nominal (stated, not measured)

Not recorded

Pressure missing in 1 of 2 rows · not reported in source
Flow missing in 1 of 2 rows · not reported in source

Condition axes: what varied and what was held constant
Axis	State	Range	Basis	Recorded
O₂	varied	13.5–15.4 % · 2 levels	reported limit	2/2
Pressure	held constant	101.3 kPa	nominal (stated, not measured)	1/2
Flow	held constant	4.0 cm/s	nominal (stated, not measured)	1/2

Placeable

2 of 2 record O₂ and can be placed (the engine can compute a distance); 1 also record pressure and appear on the charts.

Gravity

Microgravity (1) · Earth (1 g) (1)

Fuel classes

Solid · thick (2)

Flow regime

concurrent flow (2)

Materials (2)

Cast PMMA rods, concurrent flow (1) · Cast PMMA rods, 1-g upward spread (1)

Outcomes

not recorded (2)

Measured quantities

none normalized beyond O₂, pressure and flow

Data-quality flags

limit-value × 2: A reported limit: a threshold inferred by the authors from a test series, not a tested condition.
nominal-value × 2: A value stated in a document, not measured in this run.

Published records

Values transcribed from the paper (published, not a PSI table row), with the source locator and verification state of each record.

BASS-II limits: 2 records.

BASS-II limits: 2 records. Each value cell shows the normalized value and, beneath it, the original cell as it appears in the source.
Record	Inspect	Material	Fuel class	g	O₂ %	Pressure kPa	Flow cm/s	Outcome	Flags	Source locator	Verification
micro-min		Cast PMMA rods, concurrent flow	Solid · thick	µg	13.5 limittranscribed	101.3 nominaltranscribed	not recordedconcurrent flowtranscribed	not recorded	limit-value, nominal-value	Olson et al., BASS-II Summary Report, NASA/TM-20210011385 · §6.1.4.4, p. 76 (PDF p. 84)“13.5 percent O2 at a of 8 to 12 s⁻¹ is significantly lower than the observed upward flame spread limit of 15.4 percent O2”	PUBLISHEDchecked against primary source · §6.1.4.4, p. 76 (PDF p. 84)
1g-upward		Cast PMMA rods, 1-g upward spread	Solid · thick	1 g	15.4 limittranscribed	not recordedtranscribed	4.0 nominalconcurrent flowtranscribed	not recorded	limit-value, nominal-value	Olson et al., BASS-II Summary Report, NASA/TM-20210011385 · §6.1.4.4, p. 76 (PDF p. 84)“15.4 percent O2 (in normal gravity with an additional 4-cm/s forced flow (Ref. 23))”	PUBLISHEDchecked against primary source · §6.1.4.4, p. 76 (PDF p. 84)